Lithium Batteries / voltstart.

[cruising7388]

Originally Posted by wpshivers

Which would be perfect except RT is now wiring the Inverter/Charger to the charge side of the Ecotrek. So there is nothing to stop an active Inverter from draining an Ecotrek module unless the BMS also shuts down the charge-side of the Ecotrek at some point besides freezing weather.

Do you know when the relocating of the inverter from the battery discharge bus to the battery charge bus took place and why?

[wpshivers]

My early '16 CS Adventurous was wired from the Factory with the Invert/Charger on the EcoTrek Discharge side. Roadtrek recommended to my private Service Tech Dan Neeley to wire it to thew Ecotrek Charge side at his last stop at my house, as this is how they are now setting up Roadtreks, apparently to eliminate problems of the Charger side of the Inverter being unable to charge EcoTreks that have shutdown the discharge side of the EcoTrek until the User resets them. This also put all charging sources on the charge side of the Ecotrek system. Unfortunately this puts the Inverter on the charge side also.

It would be nice if Roadtrek could separate the battery connection points for Inverter/Charger but most other RV manufactures do not have separate Charge/Discharge sides of their battery systems.

It would I think require a custom Inverter design, a bit more expensive than slapping a "RoadTrek/EcoTrek" sticker on a standard off the shelf inverter......

It does make me wonder what would happen if I left the A/C on using my EcoTreks with Voltstart active. Could the EcoTreks eventually be completely drained? Leaving me with a hot interior (Not good for pets! But not a problem for me) and no house power until I could run the Underhood Generator for awhile... Perplexing question, I have to assume Roadtrek shuts down the Charge side of the Ecotrek at some point when voltage becomes too low?

[booster]

I really don't understand a bunch of this about the charge and discharge sides of the batteries. Sure would be nice to have a wiring diagram, but of course that won't happen with a Roadtrek system.

On face value, if you want to have separated charge and discharge sides of the batteries, how could you possibly be able to use a combo inverter/charger? The charger would need to be on the charge side of the batteries, and the inverter on the discharge side of the batteries, as inverter/charger units only have one set of 12v cables to them. If you put one on either the charge or discharge side it is going to tie them together or there will not be separation of charge and discharge sides.

If the inverter is on the charge side, would it then be powered from the charge side of the battery system, while the van is powered from the discharge side? Which side does the single AGM connect to?

It appears that other brands of lithium systems don't try to control everything at the batteries themselves. When they want to prevent charging when full or a problem the shut off the charging system, be it shore, alternator, or solar. The batteries all stay connected to the loads unless they need to protect themselves from a fault, and then the totally shut down. Roadtrek seems to be making it all more difficult than it needs to be, especially when trying to use the low end private label parts to do it all.

[booster]

Originally Posted by wpshivers

It does make me wonder what would happen if I left the A/C on using my EcoTreks with Voltstart active. Could the EcoTreks eventually be completely drained? Leaving me with a hot interior (Not good for pets! But not a problem for me) and no house power until I could run the Underhood Generator for awhile... Perplexing question, I have to assume Roadtrek shuts down the Charge side of the Ecotrek at some point when voltage becomes too low?

That would be the often mentioned death spiral, where the alternator does not have enough hot/idle capacity to run the AC and recharge the batteries at the same time, so the batteries lose SOC on every cycle until they are empty. Eventually, you use up the allowable number of runs of the van and you are done.

[cruising7388]

Originally Posted by booster

That would be the often mentioned death spiral, where the alternator does not have enough hot/idle capacity to run the AC and recharge the batteries at the same time, so the batteries lose SOC on every cycle until they are empty. Eventually, you use up the allowable number of runs of the van and you are done.

I think the alternator does provide some battery charge during a Voltstart sequence (probably in the area of an anemic 40 amps) although it's clearly insufficient to significantly improve the battery SOC.

The Voltstart trigger change from 12.4V to 12.8V doesn't change the ultimate result you describe but it does produce a different sequence. At 12.4V, when the last Voltstart period has finished, there is probably insufficient battery SOC to run the AC for more than a couple of minutes before the BMS shuts everything down. At 12.8V, Voltstart engages much sooner but after the final sequence when Voltstart quits, at 12.8V, the batteries are at a higher SOC and the AC will likely run substantially longer before the BMS calls it quits.

[gregmchugh]

Originally Posted by cruising7388

I think the alternator does provide some battery charge during a Voltstart sequence (probably in the area of an anemic 40 amps) although it's clearly insufficient to significantly improve the battery SOC.

The Voltstart trigger change from 12.4V to 12.8V doesn't change the ultimate result you describe but it does produce a different sequence. At 12.4V, when the last Voltstart period has finished, there is probably insufficient battery SOC to run the AC for more than a couple of minutes before the BMS shuts everything down. At 12.8V, Voltstart engages much sooner but after the final sequence when Voltstart quits, at 12.8V, the batteries are at a higher SOC and the AC will likely run substantially longer before the BMS calls it quits.

In any case, the total run time for the Air Conditioner is the same for either voltage trigger point. You get the energy prestored in the batteries and the energy from the VoltStart cycles and as you said you can adjust where in the initial battery discharge the VoltStart cycles will trigger but overall the energy available doesn’t change...

[cruising7388]

Originally Posted by wpshivers

My early '16 CS Adventurous was wired from the Factory with the Invert/Charger on the EcoTrek Discharge side. Roadtrek recommended to my private Service Tech Dan Neeley to wire it to thew Ecotrek Charge side at his last stop at my house, as this is how they are now setting up Roadtreks, apparently to eliminate problems of the Charger side of the Inverter being unable to charge EcoTreks that have shutdown the discharge side of the EcoTrek until the User resets them. This also put all charging sources on the charge side of the Ecotrek system. Unfortunately this puts the Inverter on the charge side also.

This has me somewhat confused:

What problem is corrected by shifting the charger/inverter positive lead from the battery discharge bus to the charge bus? ?

If the inverter input is pinned to the battery charging bus, how does it ever get liftoff if it's pinned to an input point? Can the charge port deliver power?

If the inverter is on the charging bus, how can it function if the battery temperature drops below 32F shutting down the charging port?

How does the fact that the inverter must be on in order for the charger to work affect alll of this?

[gerrym51]

Originally Posted by wpshivers

My early '16 CS Adventurous was wired from the Factory with the Invert/Charger on the EcoTrek Discharge side. Roadtrek recommended to my private Service Tech Dan Neeley to wire it to thew Ecotrek Charge side at his last stop at my house, as this is how they are now setting up Roadtreks, apparently to eliminate problems of the Charger side of the Inverter being unable to charge EcoTreks that have shutdown the discharge side of the EcoTrek until the User resets them. This also put all charging sources on the charge side of the Ecotrek system. Unfortunately this puts the Inverter on the charge side also.

It would be nice if Roadtrek could separate the battery connection points for Inverter/Charger but most other RV manufactures do not have separate Charge/Discharge sides of their battery systems.

It would I think require a custom Inverter design, a bit more expensive than slapping a "RoadTrek/EcoTrek" sticker on a standard off the shelf inverter......

It does make me wonder what would happen if I left the A/C on using my EcoTreks with Voltstart active. Could the EcoTreks eventually be completely drained? Leaving me with a hot interior (Not good for pets! But not a problem for me) and no house power until I could run the Underhood Generator for awhile... Perplexing question, I have to assume Roadtrek shuts down the Charge side of the Ecotrek at some point when voltage becomes too low?

I have read most of your posts on the other facebook site. I thought everything was finally working perfectly after Dan Neeley did his magic?

[gregmchugh]

Originally Posted by wpshivers

My early '16 CS Adventurous was wired from the Factory with the Invert/Charger on the EcoTrek Discharge side. Roadtrek recommended to my private Service Tech Dan Neeley to wire it to thew Ecotrek Charge side at his last stop at my house, as this is how they are now setting up Roadtreks, apparently to eliminate problems of the Charger side of the Inverter being unable to charge EcoTreks that have shutdown the discharge side of the EcoTrek until the User resets them. This also put all charging sources on the charge side of the Ecotrek system. Unfortunately this puts the Inverter on the charge side also.

It would be nice if Roadtrek could separate the battery connection points for Inverter/Charger but most other RV manufactures do not have separate Charge/Discharge sides of their battery systems.

It would I think require a custom Inverter design, a bit more expensive than slapping a "RoadTrek/EcoTrek" sticker on a standard off the shelf inverter......

It does make me wonder what would happen if I left the A/C on using my EcoTreks with Voltstart active. Could the EcoTreks eventually be completely drained? Leaving me with a hot interior (Not good for pets! But not a problem for me) and no house power until I could run the Underhood Generator for awhile... Perplexing question, I have to assume Roadtrek shuts down the Charge side of the Ecotrek at some point when voltage becomes too low?

I would hope that they shut down the charge connection when they get to some low voltage to prevent complete discharge. I expect they decided that preventing overcharging on shore power by moving the inverter to the charge connection was the better option.

[gregmchugh]

Originally Posted by cruising7388

This has me somewhat confused:

What problem is corrected by shifting the charger/inverter positive lead from the battery discharge bus to the charge bus? ?

If the inverter input is pinned to the battery charging bus, how does it ever get liftoff if it's pinned to an input point? Can the charge port deliver power?

If the inverter is on the charging bus, how can it function if the battery temperature drops below 32F shutting down the charging port?

How does the fact that the inverter must be on in order for the charger to work affect alll of this?

The likely reasons for the shift are to prevent overcharging when on shore power or to allow the battery heaters to be powered from shore power. The inverter will always see the AGM battery on the charge bus. The charge port and discharge port both go the the batteries and when they are both active everything is connected in parallel so current can flow both ways at either port. If the batteries shut down due to low temperature then the battery heaters must be engaged by providing charge current to the charge port which was done by the underhood generator before but could also be provided by shore power with the new configuration. I suspect that the power for the heaters is tapped at the charge port input before the disconnect relay so that there is not charging but the heaters are getting power.

[cruising7388]

Originally Posted by gregmchugh

The likely reasons for the shift are to prevent overcharging when on shore power or to allow the battery heaters to be powered from shore power. The inverter will always see the AGM battery on the charge bus. The charge port and discharge port both go the the batteries and when they are both active everything is connected in parallel so current can flow both ways at either port. If the batteries shut down due to low temperature then the battery heaters must be engaged by providing charge current to the charge port which was done by the underhood generator before but could also be provided by shore power with the new configuration. I suspect that the power for the heaters is tapped at the charge port input before the disconnect relay so that there is not charging but the heaters are getting power.

If the concern is overcharging by the converter/charger if connected to the battery discharge bus, how is that prevented or even mitigated by directing charging to the battery at the charging bus?

I see your point that during normal operation, even though there are separate charge and discharge terminals, for this arrangement to work, these ports are have to be internally paralleled internally. As far as I can see, the only thing that would separate the charge and discharge terminals will be when the BMS determines that battery temperature has fallen below 32 degrees and shuts down the charge port but leaves the discharge port open.
Even when the BMS shuts down the battery doesn't the charge port still have to be open to effect a reset stimulated by the AGM?

I think we agree that the battery charge bus is hard wired to the alternator, the solar controller plus the AGM battery which presumably never sees a load unless a batttery reset is effected. The inverter charger used to be connected to the battery discharge bus and if the battery shut down, it obviously would also shut down. But if the inverter now looks at the charge bus, would the same result prevail if the BMS shuts down the battery? Isn't the inverter going to continue to operate from the AGM until AGM voltage drops down to the inverter 10.5 Volt shutdown threshold voltage creating an AGM DOD that could be described as not too terrific?

[gregmchugh]

If all the charge sources are now connected to the charge port, the BMS prevents overcharging by simply disconnecting the charge port. After the batteries reach some discharge point the BMS reconnects the charge port to recharge.

[BBQ]

.

The AGM is needed for the alternator, nothing else.

A DC current is required to excite the alternator.
When the ecotrek is shut down, there is nothing to get the alternator going, thus the added AGM.


ps. ok the solar is attached to it, so that's the other duty.

[booster]

Originally Posted by gregmchugh

If all the charge sources are now connected to the charge port, the BMS prevents overcharging by simply disconnecting the charge port. After the batteries reach some discharge point the BMS reconnects the charge port to recharge.

Wouldn't that mean that the charging would keep going on and off when you were on shore power because the inverter would run off the output side wouldn't it?

[cruising7388]

Originally Posted by BBQ

.

The AGM is needed for the alternator, nothing else.

A DC current is required to excite the alternator.
When the ecotrek is shut down, there is nothing to get the alternator going, thus the added AGM.


ps. ok the solar is attached to it, so that's the other duty.

The AGM is not supplied to excite the alternator. When the BMS shuts down the battery, it can't restart and reopen the charge and discharge ports by itself. Early Etreks ran into the problem that when the BMS shut down the battery, there wasn't any way to get it back on line using the alternator or the battery charger which was precisely the symptom that Mumkin endured. The AGM was subsequently added to provide 12 Volts to the BMS remote reset module that reopens the battery charge port to the alternator or the battery charger. It serves no other purpose.

[cruising7388]

Originally Posted by gregmchugh

If all the charge sources are now connected to the charge port, the BMS prevents overcharging by simply disconnecting the charge port. After the batteries reach some discharge point the BMS reconnects the charge port to recharge.

Is this an established fact?

Assuming the fact, if the BMS shuts down the charge port while the charger/inverter is on line, what then? How does the alternator, the solar controller and the AGM react to this? Is the AGM now an alternative load for the alternator? Is the AGM now a source for the inverter? Or neither of these? Or both of these?

[gregmchugh]

Originally Posted by booster

Wouldn't that mean that the charging would keep going on and off when you were on shore power because the inverter would run off the output side wouldn't it?

With the inverter moved to the charge port then shore power charging would get disconnected from any Ecotrek that is fully charged but the AGM would always be connected to the shore charger.

The question on the old set up with the inverter on the load port was how could the BMS prevent overcharging from shore charging without disconnecting the load ports on all the Ecotreks when they all got fully charged. The shore battery charger is unstable without a battery connected so the 12 volt loads would get unstable voltage in that case. No AGM on the load side to stay connected to the shore charger. Only solution that comes to mind is to configure the shore charger such that it cannot overcharge lithium cells.

The question on the new configuration is what happens when all the Ecotreks reach minimum state of charge and all the loads are disconnected on the load port but the inverter on the charge port continues to drain the battery cells.

Someone already pointed out the solution is to have separated 12v connections on the inverter and charger functions so they can be connected to the appropriate port...

[gregmchugh]

Originally Posted by cruising7388

Is this an established fact?

Assuming the fact, if the BMS shuts down the charge port while the charger/inverter is on line, what then? How does the alternator, the solar controller and the AGM react to this? Is the AGM now an alternative load for the alternator? Is the AGM now a source for the inverter? Or neither of these? Or both of these?

It would seem there is no other control available to the BMS than to disconnect the ports?

As far as I can tell, my Mastervolt lithium system has all the components on a network with the lithium battery bank controlling the chargers directly to go into float mode at the full charge point. I expect there may be a safety disconnect at some point to protect the cells but I usually see them go to float mode.

[booster]

It certainly seems like it makes a lot more sense to shut off the charging sources, than disconnecing the batteries when full. A few simple relays to control alternator field, solar panels and 110v to the shore charger and you are good to go, I would think. I wonder if the Volta does it that way?

[gregmchugh]

Originally Posted by cruising7388

The AGM is not supplied to excite the alternator. When the BMS shuts down the battery, it can't restart and reopen the charge and discharge ports by itself. Early Etreks ran into the problem that when the BMS shut down the battery, there wasn't any way to get it back on line using the alternator or the battery charger which was precisely the symptom that Mumkin endured. The AGM was subsequently added to provide 12 Volts to the BMS remote reset module that reopens the battery charge port to the alternator or the battery charger. It serves no other purpose.

It has another purpose, it is needed to excite the alternator or solar charger (or shore power charging in this new configuration) when you need to power the battery heaters if the Ecotreks are shut down in cold weather. Without the AGM in place there would be no way to get power to the battery heaters to warm the batteries up to operating temperature without moving the van to a warmer spot or supplying external heating to the Ecotrek modules. It would seem that the battery heaters get power on the charge port before the relay so that they can operate no matter the state of the Ecotreks.